5 ms·

I'm the author of the fastest .NET version. Ask me anything about the implementation. The code is very short and simple.

• belinder 3y ago
  You wrote this on your repo > Extending short => int is more expensive than short => ushort => uint => int Can you explain why
  • ygra 3y ago
    One results in MOVSX, the other in MOVZX [1]. The difference thus is sign/zero extension when moving to the larger register. However, they seem to perform pretty much identical if I'm reading Agner Fog's instruction tables correctly. [1] https://sharplab.io/#v2:C4LghgzgtgPgAgJgIwFgBQcDMACR2DC2A3utmbjnEgGzYCWAdsNgLIAUEAFgPYBOzEAJTYAvAD5sEANylyWXDXpNWCDj36Th47G0bBBbAK56Dhrn32SZaAL5A=== https://sharplab.io/#v2:C4LghgzgtgPgAgJgIwFgBQcDMACR2DC2A3ut... EDIT: Ah, the other reply notes that this is likely only visible in a method that also does calculations and thus keeps those values in registers.
  • anonymoushn 3y ago
    if the value starts out in a register, short => int is a sign-extend instruction. short -> ushort -> int is 0 instructions.
  • buybackoff 3y ago
    The sibling comments said it sooner and better